Question 1. [10 marks] What is the difference between convection and radiation? Question 2. [10 marks) Define thermal energy and heat. Question 3. [20 marks] The direction of heat transfer across a wall is showing by the red arrow. If the temperature difference between the top and bottom is 10 C and the thermal conductivity of the wall is 1.6 W/m.K, determine: a) The heat flux. (10 marks) b) The rate of heat transfer. (10 marks) (Assume H = 2 m, W= 20 cm and L = 6 m) W Figure1: heat transfer across a wall